LANSING, Mich. (AP) — Michigan lawmakers gave final approval Tuesday to a measure that would make more low-income adults eligible for Medicaid, positioning the state to become the largest controlled by Republicans to support a key component of the new federal health care law.

In a bipartisan 75-32 vote, the House approved expanding the government health insurance program to almost a half-million Michigan residents within a few years, nearly halving the state’s uninsured. An estimated 320,000 are expected to be eligible in late March if the federal government OKs the plan.

They could have been covered as early as Jan. 1. However, the Senate — where just enough Republicans in a GOP supermajority joined Democrats to pass the bill last week after months of intense debate — fell short of putting the law into effect immediately and did not revisit the issue Tuesday.

Republican Gov. Rick Snyder, for whom Medicaid expansion was a major priority, will sign the measure after returning from a 10-day trade trip to Asia.

“I would have preferred to have gotten immediate effect, but what I would say is this is still a victory for Michiganders — both in terms of the people getting coverage and all Michiganders,” he told reporters.

Medicaid expansion is part of a strategy to ensure nearly all Americans have health insurance under the Affordable Care Act. It was designed to cover the neediest uninsured people yet became optional for states because of a Supreme Court decision.

Many GOP-led states opposed to “Obamacare” have declined the expansion, despite the U.S. government promising to cover the entire cost for the first three years and 90 percent later. Michigan is poised to become the seventh state led by a Republican governor to expand Medicaid, and just the third where the GOP also controls the Legislature — joining Arizona and North Dakota.

The program already covers one in five Michigan residents, mainly low-income children, pregnant women, the disabled and some poorer working adults. The expansion would cover adults making up to 133 percent of the poverty level — $15,500 for an individual, $26,500 for a family of three.

Snyder said Michigan’s plan is not a “generic” expansion and differs from other states that have accepted the expansion.

Republican-drawn cost-sharing provisions for 150,000 people making between 100 and 133 percent of the poverty line, along with financial incentives to lead healthy lifestyles and a plan to create individual health savings accounts, still need federal approval.

Snyder and a large coalition of backers ranging from the business and medical lobbies to advocates for the poor say offering health insurance to more low-income residents will make them healthier and minimize expensive trips to the emergency room, preventing cost-shifting to businesses and individuals with health plans.

Opponents question such a big government expansion when the U.S. is trillions of dollars in debt and are suspicious of money-saving claims. Tea party and conservative activists plan to oppose Snyder’s expected re-election bid next year because of his push to expand Medicaid coverage.

“I’ve been on Medicaid. So have members of my family. It’s not easy and it’s not a great option,” said Rep. Ed McBroom, a Republican from Vulcan in the Upper Peninsula who voted against the bill. “We seem to be focused on the overall numbers and the overall dollars rather than on the quality of care provided.”

Low-income adults without health coverage in January will not have to worry about incurring tax penalties. The federal government has decided not to penalize residents in states that decline to expand Medicaid, so Michigan residents are not expected to be fined for a delay out of their control.

Still, Democrats criticized Republicans for not covering people as soon as possible. Unlike in the House, where Republicans were evenly divided over the expansion, it was staunchly opposed by most Senate Republicans, some in shock that the bill won passage in a GOP-dominated chamber.

By taking a “procedural” vote potentially seen as aiding implementation of the federal health care overhaul, they could have faced repercussions in 2014 primary elections or later in their political careers.

The roughly three-month delay could cost the state up to $64 million in savings primarily associated with paying mental health and substance abuse treatment costs with federal Medicaid dollars.

“To the average citizen, it simply makes the majority sound petulant and petty,” said Senate Minority Leader Gretchen Whitmer, a Democrat from East Lansing. “Two of you Republican senators are keeping thousands from getting health care coverage your governor says is life and death.”